Crops for Certified Organic Pepper Production

Introduction Organic production rose to 2.3 million acres in the U.S. in 2001 (USDA-ERS, 2002). Much of the increase has been associated with the implementation of consistent federal standards for products marketed as “organic” in October 2002 (USDA/AMS, 2002). In order to meet certified organic requirements in the state of Iowa (IDALS, 2000), a soilbuilding cover crop is required for at least one out of every five years of horticulture production. The majority of organic producers incorporate cover crops prior to planting, but others have been successful using conservation, strip-, or zone-tillage, and simply leaving the mowed cover crop on the surface to help mitigate weeds and soil erosion (Abdul-Baki & Teasdale, 1993). A long-term experiment was established at the ISU Muscatine Island Research and Demonstration Farm (MIRDF) to compare pepper growth, yield, insect populations, harvest cullage and postharvest weight loss under conventional and organic management. Treatments from the first 3 years (1998 to 2000) consisted of combinations of two synthetic fertilizer and three compost-based certified organic soil amendments. In addition to the compost treatments, effects of a cover crop of hairy vetch (Vicia villosa Roth) and rye (Secale cereale L.) were evaluated in the organic system from 1999 to 2002. Pepper growth, harvest weight and marketable fruit numbers were similar in conventional and organic production systems from 1998 to 2002 when 100 lb. N/A was applied through synthetic fertilizer or compost/organic fertilizer. Zonetillage organic pepper production resulted in significantly reduced growth and pepper weight in two out of three years at the MIDRF. In 2003, a third-year evaluation of the organic poultry litter-based fertilizer and gypsum soil amendment was conducted. In addition, hairy vetch cover crops were evaluated for a fourth year. Due to three years of inconsistent results with the zone-tilled hairy vetch treatment, this treatment was modified in 2002 to include a side-dress application of organic fertilizer (50 lb N/A) after plant establishment. The additional side-dress application resulted in a significant increase in plant production in 2002.